Ni-Al Bronze in Molten Carbonate Manufactured by LPBF: Effect of Porosity Design on Mechanical Properties and Oxidation

Abstract

Fuel cell technology has developed due to diminishing dependence on fossil fuels and carbon footprint production. This work focuses on a nickel–aluminum bronze alloy as an anode produced by additive manufacturing as bulk and porous samples, studying the effect of designed porosity and thermal treatment on mechanical and chemical stability in molten carbonate (Li2CO3-K2CO3). Micrographs showed a typical morphology of the martensite phase for all samples in as-built conditions and a spheroid structure on the surface after the heat treatment, possibly revealing the formation of molten salt deposits and corrosion products. FE-SEM analysis of the bulk samples showed some pores with a diameter near 2–5 μm in the as-built condition, which varied between 100 and −1000 μm for the porous samples. After exposure, the cross-section images of porous samples revealed a film composed principally of Cu and Fe, Al, followed by a Ni-rich zone, whose thickness was approximately 1.5 µm, which depended on the porous design but was not influenced significantly by the heat treatment. Additionally, by incorporating porosity, the corrosion rate of NAB samples increased slightly.

The Effect of Adding CeO2 Nanoparticles to Cu–Ni–Al Alloy for High Temperatures Applications

“…In addition, Figure 2 shows that during the initial stage, the weight increased rapidly for all the Cu–50Ni–5Al samples, which was lower for Cu–50Ni–5Al + 1 wt.% CeO 2 –NPs, reaching a maximum weight gain of only 1.2% at 504 h of exposure. For a longer exposure time, the weight gain reaches a stationary state associated with a passive oxide layer [ 16 ] formed after 80 h for Cu–50Ni–5Al + 3 wt.% CeO 2 –NPs, and after 160 h for Cu–50Ni–5Al + 0 wt.% CeO 2 –NPs. It should be noted that with 5 wt.% CeO 2 –NPs, the weight gain did not reach a plateau of up to 504 h of exposure, like the sample with 3 wt.% CeO 2 –NPs.…”

“…The Cu–50Ni–5Al samples were immersed in molten eutectic Li 2 CO 3 –K 2 CO 3 (62–38 mol.%) [ 14 , 15 ] for 504 h (21 days) in an aerated atmosphere or not–controlled medium at 550 ± 5 °C. The gravimetric measurements of samples were carried out as described previously by Arcos et al [ 16 ]. The samples were removed and cleaned to eliminate the deposits and corrosion products on the surface.…”

“…Figure 2 shows the effect of CeO2−NPs on the weight gain of the Cu−50 ples after exposure to molten carbonates, revealing a reduction in the weig CeO2−NPs. In addition, Figure 2 shows that during the initial stage, the weig rapidly for all the Cu−50Ni−5Al samples, which was lower for Cu−50Ni−5 CeO2−NPs, reaching a maximum weight gain of only 1.2% at 504 h of exp longer exposure time, the weight gain reaches a stationary state associated w oxide layer [16] formed after 80 h for Cu−50Ni−5Al + 3 wt.% CeO2−NPs, an for Cu−50Ni−5Al + 0 wt.% CeO2−NPs. It should be noted that with 5 wt.% Ce weight gain did not reach a plateau of up to 504 h of exposure, like the sample CeO2−NPs.…”